Racemisation represents the key step in so-called deracemisation processes, which allow the quantitative transformation of a racemate into a single stereoisomeric product. Many chemical racemisation protocols require harsh reaction conditions and have therefore to be conducted ex-situ after separation of the material to be racemised from the chiral product(s) formed during kinetic resolution. Only few racemisation methods are consistent with mild reaction conditions and thus can be used in-situ, most notably transition metal catalysts.
The enzymatic interconversion of an acyloin (acetoin) has been ascribed to the action of a so-called acetoin racemase, whose existence was only postulated for the organism Klebsiella (M. Voloch, M. R. Ladisch, V. W. Rodwell, G. T. Tsao, Biotechnol. Bioeng. 1983, 25, 173-183.) but detailed data are not available.